Laos has a land area about the same as great britain but only four million in population, where many are members of hill tribes ensconced in the virtually inaccessible mountain valleys of the north.

You have been tasked with sorting the rock samples shown into three categories, with two rocks in each category. what attribute would you use to sort these rocks? which rocks would be in each category? rocks: obsidian, coquina limestone, granite, soapstone, pumice, and gneiss.